‘The lesson of histories’ explores the lessons from histories of plague. These lessons highlight the importance of cultures and institutions, contexts and agents in creating epidemics and reactions to them. They show that the ways in which people think and live, the kinds of information available to them, and the kinds of behaviour they adopt make a difference. Whether they were effective or not, the quarantine policies invented and developed in early modern Europe demonstrated the role played by political cultures and political institutions in shaping reactions to plague. The responses to new or ‘re-emerging’ diseases, which seemed to threaten fresh pandemic disasters, including HIV/AIDS and COVID-19, have shown that public and private responses to them will be necessary, diverse, and divisive, and no more certain to succeed than they were in the past.